Many vehicles are equipped with rear mounted receiver trailer hitches used for towing and as an attachment point for many other cargo accessories. These types of trailer hitches typically include a receiver opening or cavity used for the receipt of a draw bar. The receiver opening comes in various sizes depending upon the towing capabilities thereof. For example, receiver-type trailer hitch assemblies are typically offered with a square receiver opening of 1.25 inches (32 mm) for Class I/II, 2 inches (51 mm) for Class III/IV/V, and some Class V hitches are available in 2.5 inches (64 mm) opening sizes.
A draw bar having a shank includes outer dimensions slightly smaller than the internal dimensions of the receiver opening and is normally slidable within the receiver opening. The draw bar is typically connected to the receiver opening by a pin inserted through the two tubular portions thereof and locked or clipped to prevent removal of the draw bar from the trailer hitch. The two components are both toleranced to ensure that the draw bar can be freely inserted and removed from the receiver opening.
The draw bar may include a standard ball-mount for engaging with the coupler of a towed vehicle or other wheeled vehicle. Another popular use for receiver trailer hitches is the use as a coupling device for installing cargo accessory such as equipment racks onto the vehicle. Bicycle carrier racks, ski carriers, storage boxes and other types of carriers have been designed to use the above-described draw bar to engage within a receiver opening. This provides a universal system that allows a vehicle user to use various towed vehicles and accessory carriers with a single coupling system.
A particular problem with the use of these receiver hitch assemblies is the clearance between the internal dimensions of the receiver opening and the external dimensions of the draw bar. The tubular portions thereof by necessity must have sufficient clearance to be able to be easily telescoped together. However, this clearance between the two tubular portions allows relative movement between them. The draw bar tends to rattle or chatter within the receiver opening during use. This rattle or chatter can be a distraction to the driver and can cause premature wear to the components.
A need is therefore identified for an improved apparatus whereby the movement between the receiver opening and the draw bar is minimized. Further, there is a need for an anti-rattle apparatus that is easy to operate and is effective.